1. Field of the Invention
The invention relates to a process for triggering an electrically actuated motor vehicle door lock or the like, which is actuated electrically from a mechanical or electromechanical actuating handle. More specifically, to the triggering of a motor vehicle door lock in a largely closed external housing having a latch, made preferably as rotary latch, and having a detent pawl which keeps the rotary latch in the closed position, an electric drive for the detent pawl, the detent pawl being raisable off of the catch of rotary latch by the drive, and having microswitches which indicate the position of the detent pawl and the position or actuation state of the actuating handle. The invention also relates to the corresponding circuits for performing the process.
2. Description of Related Art
A related process is known for a motor vehicle side door lock, which in principle can also be used for trunk lid locks and tailgate locks. The prior art (published German Application 32 42 527) is characterized by an extensive electric motor drive, by which both the latch and the detent pawl are driven, the latch in the sense of a locking aid, and the detent pawl in the sense of electric motor triggering. The prior art specifically shows only a single electric drive motor which can be drive-coupled both to the latch (in one direction of rotation) and also to the detent pawl (in the other direction of rotation) via a self-locking, step-down gearing which works in two directions of action. Only the triggering of the electric motor drive in its relation to the detent pawl is of interest relative to this invention.
In the noted prior art, the latch is provided with a double lock-in position that is conventional for side door locks, and specifically, is made as a fork latch with a front catch on the leading fork latch leg and a main catch on the following fork latch leg. The latch is held both in the front latch position and also in the main latch position by the detent pawl which is tension-loaded with a corresponding catch projection. The detent pawl is supported on a bearing axle and is made with two arms, the second arm of the detent pawl pointing away from the catch projection having an actuation surface.
The electric motor drive has a drive element made as a pinion to which a driver in the form of a cam disk is attached with a stop edge which thus forms an eccentric driver. This drive element can only be rotated in one direction, and therefore is not reset, but always returns to its original position again as it continues to turn in the direction of rotation. By turning the drive element in the lifting and turning direction, the driver strikes the actuating surface of the detent pawl and lifts the catch projection of the detent pawl off the main catch of the rotary latch.
In the aforementioned prior art, starting of the electric drive from. the initial position (readiness position) is triggered by actuating a handle, for example, an exterior door handle, and this actuation switches a microswitch. After the detent pawl has been successfully raised off the main catch by means of the driver, the driver strikes another microswitch and turns off the electric motor drive again. The detent pawl thus remains in the lifted position. In this way, the rotary latch can reach its open position unhindered by the detent pawl and the detent pawl, therefore, does not drop into the front catch of the rotary latch. This state lasts until the handle is again released. Release of the handle switches the microswitch again, which thus turns on the electric motor drive again. The cam disk which forms the driver continues to turn into its initial position (readiness position) in which the detent pawl falls back again or comes to rest on the leading fork latch leg under reset spring force. When the motor vehicle door or lid is closed the detent pawl can, therefore, drop into the front catch on the latch again under spring force.
The above explanation illustrates that the proper function of keeping the detent pawl open presupposes positive actuation of the handle by an individual. When an individual releases the handle before the rotary latch has reached the open position, it can happen that the detent pawl drops into the front catch of the rotary latch, although the door or lid is not yet open. This is not a problem in this type of drive engineering since further pulling on the handle allows the trigger cycle for the detent pawl to be repeated.
A more modern version of this electrically actuated motor vehicle door lock is known (published European Patent Application 0 589 158) in which lifting of the detent pawl is caused via a small electric drive in an otherwise largely closed external housing, especially via a solenoid. Triggering takes place from a mechanical or electronic actuating handle (handle or remote control) using various microswitches, among others; these rnicroswitches are used for scanning the position of the detent pawl and the position of the drive. Here, complete integration of the construction in the small external housing of the motor vehicle door lock is obtained, as is fully electronic triggering with control logic.
In the aforementioned triggering of an electrically actuated motor vehicle door lock with a solenoid as the drive of the detent pawl, the problem of the detent pawl dropping again can be solved relatively easily by a corresponding triggering of the solenoid, if specifically the rotary motion of the rotary latch is scanned until the open position is reached. This is also provided here. Consideration of this "snow load function" is of varied importance in different applications.
The above explained motor vehicle door locks or the like operate with microswitches for triggering. The use of microswitches and self-locking drives which run in one direction has the advantage that energy is only consumed when it is actually needed. The electric drive motor does not run into a block in order to be turned off by the then detected increase of the supply current. The electric motor drive need not operate against the force of a return spring either. Very low operating voltages can be used and power supply voltages of a few volts are sufficient. The gearing is protected since stops need not be struck. For this reason, as before, the use of microswitches for triggering generic motor vehicle door locks is quite popular. Here, it is not overlooked that microswitches can be a problem now and then with respect to their operating reliability.
In the above explained known process, user-friendliness is always a special concern. Processes for triggering electrically actuated motor vehicle door locks should proceed as much as possible such that an operator or user can act essentially as before, as is customary from the operation of mechanical or electromechanical motor vehicle door locks of the conventional type. To this extent, however, there is the problem that the known processes are not yet optimized with respect to user friendliness.